French aircraft pounded Islamist rebels in Mali for a second day on Saturday and neighboring West African states sped up their plans to deploy troops in an international campaign to prevent groups linked to al Qaeda expanding their power base.

France, warning that the control of northern Mali by the militants posed a security threat to Europe, intervened dramatically on Friday as heavily armed Islamist fighters swept southwards towards Mali's capital Bamako.Under cover from French fighter planes and attack helicopters, Malian troops routed a rebel convoy and drove the Islamists out of the strategic central town of Konna, which they had seized on Thursday. A senior army officer in the capital Bamako said more than 100 rebel fighters had been killed.

A French pilot died on Friday when rebels shot down his helicopter near the town of Mopti. Hours after opening one front against al Qaeda-linked Islamists, France mounted a commando raid to try to rescue a French hostage held by al Shabaab militants in Somalia, also allied to al Qaeda, but failed to prevent the hostage being killed.

French President Francois Hollande made clear that France's aim in Mali was to support the West African troop deployment, which is also endorsed by the United Nations, the European Union and the United States.

Western countries in particular fear that Islamists could use Mali as a base for attacks on the West and expand the influence of al Qaeda-linked militants based in Yemen, Somalia and North Africa.

"We've already held back the progress of our adversaries and inflicted heavy losses on them," Hollande said. "Our mission is not over yet."

A resident in the northern city of Gao, one of the Islamists' strongholds, reported scores of rebel fighters were retreating northward in pickup trucks on Saturday.

"The hospital here is overwhelmed with injured and dead," he said, asking not to be identified for fear of reprisals.

In Konna, a shopkeeper reported seeing scores of dead Islamist fighters piled in the streets, as well as the bodies of dozens of uniformed soldiers.

A senior official with Mali's presidency announced on state television that 11 Malian soldiers had been killed in the battle for Konna, with around 60 others injured.

Human Rights Watch said around 10 civilians had died in the violence, including three children who drowned trying to cross a river to safety. It said other children recruited to fight for the Islamists had been injured.

With Paris urging West African nations to send in their troops quickly, Ivory Coast President Alassane Ouattara, chairman of the regional bloc ECOWAS, kick-started a U.N.-mandated operation to deploy some 3,300 African soldiers.